docs(agents): Consolidate agent instructions and add mission-critical development standards

- Merge copilot-instructions.md into AGENTS.md as single source of truth
- Remove redundant .github/copilot-instructions.md file
- Add comprehensive mission-critical development standards section:
  * Documentation requirements (README, doc/, codeDocs/)
  * Code quality and formatting (pylint, mypy, PEP 8)
  * Testing requirements (unit, integration, smoke, e2e)
  * Code documentation maintenance
  * CI/CD pipeline requirements
  * .gitignore maintenance
  * Mission-critical quality checks
  * Security requirements (OWASP, PII, secrets, dependencies)
- Add pre-commit quality checklist template
- Enhance architecture documentation with build/pipeline details
- Add validation pipeline timing requirements
- Document known issues and workarounds
- Clarify branch strategy and Azure DevOps integration

All AI agents must now follow comprehensive quality standards including:
- Documentation updates across all doc/ folders
- Complete test coverage (unit, integration, smoke, e2e)
- Code quality checks (linting, formatting, type checking)
- Security compliance (CodeQL, secrets detection, PII filtering)
- CI/CD pipeline maintenance
- Repository hygiene (.gitignore, PR templates)

Author: vinod0m